Lithium-ion rechargeable batteries have been developed for hybrid electric vehicle (HEV) and plug in HEV applications by several battery suppliers in the US. However, there are still significant challenges to develop lithium-ion batteries to meet the high energy density requirements for EV applications. Silicon has demonstrated high gravimetric density (3579 mAh/g at Li15Si4), almost 10 times higher than graphite anode materials (372 mAh/g). High energy density Si based anode material has the potential to fulfill the energy density requirements for EV applications, when combined with high voltage or high capacity cathode materials. However, Si anode materials tend to have lower first cycle coulombic efficiency compared to graphite materials. The smaller the Si particle size, the larger the first cycle irreversible capacity. The first cycle efficiency may be as low as 50% for nanosize Si materials. Lithium ions are consumed during first lithiation to form surface coatings on Si, leading to a shortage of cycleable lithium in the cell. This lithium shortage can cause shift of electrode potentials during cell operation, resulting in fast fading of the entire cell system.
It has recently been proposed to use FMC Corporation's proprietary stabilized lithium metal powder (SLMP™) to increase the lithium content of battery electrodes by either surface application or slurry application, as described in the FMC single page bulletin (Appendix) entitled “For More Charge Use Li, For Maximum Charge Use FMC's SLMP Technology”. See also the FMC one page article entitled “Incorporation of Stabilized Lithium Metal Powder (SLMP™) into High Energy Li-ion Batteries”, Li, et al., and U.S. Pat. Nos. 5,567,474; 5,776,369; 5,976,403; 6,706,447; and 7,276,324.